19921618601 has 2 divisors, whose sum is σ = 19921618602. Its totient is φ = 19921618600.

The previous prime is 19921618547. The next prime is 19921618603. The reversal of 19921618601 is 10681612991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11777458576 + 8144160025 = 108524^2 + 90245^2 .

It is a cyclic number.

It is not a de Polignac number, because 19921618601 - 2²⁶ = 19854509737 is a prime.

Together with 19921618603, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19921618603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9960809300 + 9960809301.

It is an arithmetic number, because the mean of its divisors is an integer number (9960809301).

Almost surely, 2^19921618601 is an apocalyptic number.

It is an amenable number.

19921618601 is a deficient number, since it is larger than the sum of its proper divisors (1).

19921618601 is an equidigital number, since it uses as much as digits as its factorization.

19921618601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 44.

The spelling of 19921618601 in words is "nineteen billion, nine hundred twenty-one million, six hundred eighteen thousand, six hundred one".